1. Field of the Invention
The present invention relates to a medical laser device.
2. Description of the Related Art
In certain invasive medical procedures thermal or other energy is administered to a patient with beneficial effects. For example, energy can be used to detect a tumour or a region of the body, or to destroy or denature diseased or malfunctioning body tissue. One example of this type of treatment is disclosed in U.S. Pat. No. 6,095,149 which describes the treatment of invertebral disc abnormalities with thermal energy. Other types of medical treatment utilise laser energy, for example endovenous laser treatment (EVLT), wherein laser energy is delivered to the inner wall of a vein.
Laser energy may be delivered to an area of the body by means of an optical fiber such as a bare-tipped optical fiber. However, the tips of such optical fibers could cause trauma to soft tissues. Therefore, for some invasive applications it is not desirable to insert the optical fiber directly into the body tissue. Instead, the optical fiber is typically inserted into a flexible introducer sheath which acts to guide and protect the optical fiber (and also the surrounding tissue) whilst it is being inserted into the region of the body to be treated. An introducer sheath is frequently inserted into body tissue over a guide wire and then the optical fiber can be inserted once the introducer sheath is in place in the body.
In use the introducer sheath is often positioned so that the optical fiber protrudes a few millimeters or centimeters from the end of the introducer sheath so as to deliver laser energy efficiently from the tip of the fiber to the surrounding tissue.
It is known to detect the protrusion of the optical fiber from the introducer sheath using ultrasound and/or direct visualization of a red aiming laser beam from the optical fiber through the skin. However, these methods are unsatisfactory for a number of reasons. The use of ultrasound requires additional equipment which is expensive and complicates the procedure. Visualization of the laser beam is imprecise and at best only a guide and then only in regions of the body which are sufficiently close to the surface of the skin. Therefore, conventional techniques are not suitable for use in a wide range of applications.
Furthermore, as a result of it being difficult for an operator or surgeon to determine when the distal end of the optical fiber is approaching the distal end of the introducer sheath, damage can readily occur to the soft tissues if the optical fiber is initially accidentally extended beyond the introducer sheath. As a result an operator must insert the optical fiber very slowly into the introducer sheath and must proceed cautiously at all times which makes the procedure slow.
It is therefore desired to provide an improved medical laser device.